Stock food and process of making same



, comparable to a Patented June 10, 1924.

UNITED STATES 1,496,833 PATENT OFFICE.

EARL C. SHERRARD, 0F MADISON, WISCONSIN. DEDICATED, IBY HEBNE ASSIGNMENTS, TO THE PEOPLE 01 THE UNITED STATES OF AMERICA.

STOCK FOOD AND IPROCESS OF MAKING SAME.

K0,,Drawin g.

Application filed November 27, 19532. Serial No. 608,080.

(FILED UNDER THE ACT OF MARCH 3, 1,883, 22 STAT. 13., 625.)

T a all whom it may concern:

Be it known that I, EARL C. SHERBARD, a citizen of the United States of America, and an employee of the Department of Agriculture, residing in Madison, Wisconsin, whose post-office address is Department of Agricu ture, Madison, Wisconsin, have invented a certain new and. useful Stock Food and Process of Making Same, of which the following is a specification.

This application is made under the act of March 3, 1883, Chapter 143 (22 Stat, 625), and the invention herein described and claimed may be used by the Government of the United States or any of its olficers or employees in the prosecution of work for the Government and also by an erson in the United States, either in pu he or private work, without payment to me of any royalty.

thereon.

My invention consists 1n-su'b ectmg sawdust, finely comminuted wood waste or other cellulose containing material to the action of a dilute acid under pressure for varying periods of. time. This treatment causes a portion of the wood to hydrolyze with a production of about 18 to 25 per cent sugar. After leaching the sugar from the digested dust with hot water, neutralizing the acid with a suitable reagent such as lime, calcium, carbonate, soda, ash, etc., the settled or filtered li uoris evaporated. The heayy syrup obtaine by evaporation of the sugar solution is then mixed with the partia 1y dried extracted dust and the whole evaporated to about eight to fifteen per cent moisture. The product produced in this wa is aim and may be use as such in a standar ration.

The process of manufacturing this material in more detail is as follows:

The wood in the form of sawdust or finely M shredded slabs andedgings is placed in adigester, preferably a rotating di ester, together with sufficient water to mafirethe ratio of water to wood about 1 :1 or 2.5 :1 after the digestion is complete. The acid is introduced at the same time with the water in call antities corresponding to 0.5 to 2.5% of t e d weight of the wood. ,The per cent of aci required will vary somewhat according to the time of cooking and the steam pressure used. The digester is then closefi cook of 10 to 20 minutes with 1.8

tery or other extraction a' paratus.

and steam admitted until the pressure has reached 100-120 unds for 10 to 20 minutes as noted below. e pressure may be varied accordlng to the time of cooking or to the concentration of acid used. For a standard er cent acid the steam pressure should be a out 120 pounds. The maximum pressure should be reached as rapidly as possible after admlttin the steam.

en the di estion iscomplete the digester is quick y connected to a blow-ofi' pipe leading to acondenser or to the open air, and the pressure relieved. By condensmg the blow olf, considerable quantities of volatile oil can be recovered from coniferous woods. The digested wood is then removed from the digester and the sugars extracted with water in leaching towers, difiusion e quantity of water used will spend upon the nature of the wood and its state of comminution. As a general rule a quantity of water equivalent to three or four times the original weight of the wood is sufiicient to remove the greater part of the acid used .as the hydrolyzing agent. The solution thus obtained is then neutralized with a suitable neutralizin agent until the liquor shows an acidity of our to five degrees (Am). This neutralization removes not only "the greater part of the acid introduced as the catalytic agent but also the greater part of the oranic acid such as acetic and formic acids ormed during the digestion. This extractionand subsequent neutralization of the acids is considered an important and vital step in the process.

fter the partially neutralized solution has been allowed to settle or, if necessary, filtered, the clear liquor is evaporated preferably under reduced pressure, to a thick molasses; This molasses is then added to the extracted dust which may, or may not have been previously pressed or partially dried or both. After mixing the material is placed in an oven or continuous dryer and the moisture content reduced to 8 to 15 er cent.

The concentration of the aci used as the hydrolyzing agent is varied according to the pressure or to the period of time of cookin For example, a quantit of acid correspon ing to 1.8 per cent of t e dry weight of the Q 1,4ee,esa wood should be'used for cooking periods of wood. This can be done either by screening from to minutes, while for s orter pe before digestion or after the extraction of riods the acid strength should be increased.

In the same way when longer periods are required, the concentration of acid may be materially lowered in order to avoid a decomposition of the sugars, a reaction that occurs when the acidity pressure or time of cooking is increased.

In the same way the quantity of water used should be varied according to the time of cooking. For periods of from 15 to 20 minutes or less and at a steam pressure of 115 to 120 ounds the ratio of water to dry wood shou d be1.25 to 1 inclusive of the moisture originally; contained in the wood. For longer perio the uantityn of water should be reduced in or or to compensate.

for the condensation of steam.

The pressure used for cooking the material is dependent upon the concentration of acid used and upon the length of the cooking period. As noted above for a concentration of acid corresponding to 1.8 per cent of the d .weight of the wood and a cookerio of 10 to 20 minutes a pressure of 115 to 120 pounds would be most desirable. For longer digestion periods and greater concentrations of acid the ressure should be somewhat reduced Whl e for shorter riods and lower concentrations of acid it should be slightly increased.

In the same m the time of cooking 1s degendent upon t e concentration of acid an upon the pressure. While the standard cook mentioned above reduces the largest quantity of total reducing sugars a longer period roduces a slightly greater per cent of the exose sugars and at the same time decomposes a part of the pentoses with a production of formic and acetic acid. Although the hexoses have a ater food value it is problematical who or the increased yield compensates for the great expense involved in the longer cooking period.

The evaporation of the sugar solution should be carried out under reduced pressure and at a temperature not ater than 95 de centigrade. It has n foun that e en ar content of the final product gradually ecreases upon standing if the moisture content is'in excess of 15 r cent. For this reason it is essential that e prod uct be dried to about eight to fifteen per cent moisture. The drying should be carried out in an oven or continuous dryer at A a temperature of 70 to 90 degrees to avoid decomposition of the The material is ve easil dried and after being dried to e t or fi 11 per cent moisture it kegps inde itely. The moisture content sho d in no, case exceed 15 per cent; otherwise it would spoil on standing.

It has also been foun desirable to remove the larger pieces of bark and undigested dtod the sugar and acid. It has been found that the moist extracted dust is more easily screened than the original dust and it is thought that the increased ease of o ra tion more than outweighs the increase cost of handlingthe screenings during digestion and extraction. The loss of materia upon screening the extracted dust amounts to about five per cent of the total material placed on. the screen.

I prepared a stock food from eastern white pine in accordance with the process described above and it was found to be characterized by containing cellulose which difiers from that in the ori 'n'al material in being almost wholly solub e or capable of formin a colloida solution in a 17 per cent so ution of sodium hydroxide and containing practically the same quantity of ligneous material as the original wood.

I claim:

1. A rocess for preparing a stock food from ce ulose contaimn material which consists in subjecting sai material .to a digestion for 10 to 20 minutes at a steam pressure of 100 to 120 pounds in the (presence of a quantity of acid equivalent to .5 per cent to 2.5 r cent of thedry weight of the ori 'na material, then extractinghghe mass wi hot water, partially neutra the acids in the solution so obtained with a neutralizing ent, such as lime, sttling to remove in'solu le material, decanting, and, after evaporation to a thick syrup, mixing the syru with the solid extracted residue from which part of the moisture has been removed.

2. A rilrocess for preparing a stock food from ce ulose containm material which consists in subjecting sai material to a digestion for 10 to 20 minutes at a steam pressure of 100 to 120 pounds in the presence of aquantity of acid equivalent to 0.5 per cent to 2.5 per cent of the dry weight of the original material and in the presence of suflicient water to make the ratio of water material from 1:1 to 2.5 :1 after digestion is complete, then extractin the mass with hot water, partially neutra sing the acids E the solution with a neutralizing a nt an as lime, settling to remove inso uble uilte'ritl, decanting, and, after evaporation to 1 thick syrup, mixin the syrup with the solid extracted residue m w ic part of the moisture has been removed.

3. Aprocess for preparing a stock food from ce lulose con material which consist! in subjecting sai material to a digestion for 10 to 20 minutes ata steam pressure of 100 to 120 nude in the presence of a quantity of aci equivalent to 0,5 per cent to 2.5 per cent of the dg weight of he original material and in e presence of III sufiieient water to make the ratio of water a art of the water has been removed, and 10 to dry material from 1 :1 to 2.5 :1 after digessu sequently drying the .whole to a. moisture tion is complete, then extracting the mass content of 8 to 15 per cent.

with hot water, partial]; neutralizin the In testimony whereof, I aflix my signature acids in the solution with a neutra izing in the presence of two subscribin witnesses.

agent, such as lime, settling to remove in- EARL G. SHE RABD. sq uble material, decanting, and, after evap- Witnesses: oration to a thick syrup, mixing the syru 1 L. F. Hnwwr,

with the solid extracted residue from whic Emma'r Bummer. 

